Rich tropical moisture surged into the state on August 18, 2013 as a wedge front/warm front retreated northward. Deep layer shear was sufficient for rotation to produce supercells. One of these supercells interacted with this boundary and produced a strong EF-1 tornado in Heard County.

Survey Summary: A National Weather Service survey team determined that a tornado touched down just inside the Georgia-Alabama line in Heard County. A mobile home sustained roof damage and its porch was destroyed as the tornado tracked northeastward, paralleling Upper Caldwell Road. The most significant damage was as the tornado crossed upper Caldwell Road, snapping dozens of trees. The tornado left a path around 0.4 miles in length. Numerous trees were snapped in its path.

Damage to a mobile from the Heard County tornado.

Snapped trees from the Heard County tornado.

Radar image of reflectivity (left) and storm relative velocity (right) from a few minutes before the Heard County tornado touched down.

So how rare are August tornadoes? Typically the number of tornadoes for the month of August in north and central Georgia is low (see the chart below) - the exception to this though is during tropical cyclones as was evidenced by Katrina and Fay.